For the second time in less than three weeks, United were beaten 2-1, having led away from home, and looked stumped while attempting to salvage the game.

United took the lead through Memphis but were undone by Hector Moreno and Luciano Narsingh's headers either side of the interval.

Captain for the night, Smalling was denied one-on-one with United ahead after a captivating surge forward and Memphis also wasted a presentable chance at 1-1, shooting straight at goalkeeper Jeroen Zoet.

The Reds created little of note when behind and Smalling felt they were too blunt up front.

"We missed that cutting edge in the final third," he said.

Mata had a poor night in attack for United

"In the first-half, they scored from their only chance and they punished us on the break.

"It’s a very disappointing night. We’ve got a lot to learn."

Mata squandered a great chance at 2-1

Smalling also revealed how upset United's players were by Luke Shaw's double fracture in the first-half.

Juan Mata signalled almost immediately that Shaw had to be substituted following Moreno's challenge, while Ander Herrera had anguish etched on his face.

United concded careless goals

Smalling attempted to rally his teammates during the lengthy stoppage as Shaw was treated but admitted the situation was saddening for him and his colleagues.

"I didn’t see it [the Shaw injury] but a few of the players witnessed it," Smalling added.